/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.apache.coyote.http11.upgrade;

import org.apache.tomcat.jni.OS;
import org.apache.tomcat.jni.Socket;
import org.apache.tomcat.jni.Status;
import org.apache.tomcat.util.net.AprEndpoint;
import org.apache.tomcat.util.net.SocketWrapper;

import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;

public class AprServletOutputStream extends AbstractServletOutputStream {

	private static final int SSL_OUTPUT_BUFFER_SIZE = 8192;

	private final AprEndpoint endpoint;
	private final SocketWrapper<Long> wrapper;
	private final long socket;
	private final ByteBuffer sslOutputBuffer;
	private volatile boolean closed = false;

	public AprServletOutputStream(SocketWrapper<Long> wrapper,
	                              int asyncWriteBufferSize, AprEndpoint endpoint) {
		super(asyncWriteBufferSize);
		this.endpoint = endpoint;
		this.wrapper = wrapper;
		this.socket = wrapper.getSocket().longValue();
		if (endpoint.isSSLEnabled()) {
			sslOutputBuffer = ByteBuffer.allocateDirect(SSL_OUTPUT_BUFFER_SIZE);
			sslOutputBuffer.position(SSL_OUTPUT_BUFFER_SIZE);
		} else {
			sslOutputBuffer = null;
		}
	}

	@Override
	protected int doWrite(boolean block, byte[] b, int off, int len)
			throws IOException {

		if (closed) {
			throw new IOException(sm.getString("apr.closed", Long.valueOf(socket)));
		}

		Lock readLock = wrapper.getBlockingStatusReadLock();
		WriteLock writeLock = wrapper.getBlockingStatusWriteLock();

		try {
			readLock.lock();
			if (wrapper.getBlockingStatus() == block) {
				return doWriteInternal(b, off, len);
			}
		} finally {
			readLock.unlock();
		}

		try {
			writeLock.lock();
			// Set the current settings for this socket
			wrapper.setBlockingStatus(block);
			if (block) {
				Socket.timeoutSet(socket, endpoint.getSoTimeout() * 1000);
			} else {
				Socket.timeoutSet(socket, 0);
			}

			// Downgrade the lock
			try {
				readLock.lock();
				writeLock.unlock();
				return doWriteInternal(b, off, len);
			} finally {
				readLock.unlock();
			}
		} finally {
			// Should have been released above but may not have been on some
			// exception paths
			if (writeLock.isHeldByCurrentThread()) {
				writeLock.unlock();
			}
		}
	}

	private int doWriteInternal(byte[] b, int off, int len) throws IOException {

		int start = off;
		int left = len;
		int written;

		do {
			if (endpoint.isSSLEnabled()) {
				if (sslOutputBuffer.remaining() == 0) {
					// Buffer was fully written last time around
					sslOutputBuffer.clear();
					if (left < SSL_OUTPUT_BUFFER_SIZE) {
						sslOutputBuffer.put(b, start, left);
					} else {
						sslOutputBuffer.put(b, start, SSL_OUTPUT_BUFFER_SIZE);
					}
					sslOutputBuffer.flip();
				} else {
					// Buffer still has data from previous attempt to write
					// APR + SSL requires that exactly the same parameters are
					// passed when re-attempting the write
				}
				written = Socket.sendb(socket, sslOutputBuffer,
						sslOutputBuffer.position(), sslOutputBuffer.limit());
				if (written > 0) {
					sslOutputBuffer.position(
							sslOutputBuffer.position() + written);
				}
			} else {
				written = Socket.send(socket, b, start, left);
			}
			if (Status.APR_STATUS_IS_EAGAIN(-written)) {
				written = 0;
			} else if (-written == Status.APR_EOF) {
				throw new EOFException(sm.getString("apr.clientAbort"));
			} else if ((OS.IS_WIN32 || OS.IS_WIN64) &&
					(-written == Status.APR_OS_START_SYSERR + 10053)) {
				// 10053 on Windows is connection aborted
				throw new EOFException(sm.getString("apr.clientAbort"));
			} else if (written < 0) {
				throw new IOException(sm.getString("apr.write.error",
						Integer.valueOf(-written), Long.valueOf(socket), wrapper));
			}
			start += written;
			left -= written;
		} while (written > 0 && left > 0);

		if (left > 0) {
			endpoint.getPoller().add(socket, -1, false, true);
		}
		return len - left;
	}

	@Override
	protected void doFlush() throws IOException {
		// TODO Auto-generated method stub
	}

	@Override
	protected void doClose() throws IOException {
		closed = true;
		// AbstractProcessor needs to trigger the close as multiple closes for
		// APR/native sockets will cause problems.
	}
}
